Stihl 291 Manual

The Stihl 291 is a professional-grade gasoline-powered chainsaw designed for demanding cutting tasks. It features a powerful engine with advanced anti-vibration technology, an easy-start system, an automatic oiler, a side-access chain tensioner, and a Quickstop® inertia-activated chain brake for enhanced safety. Below are key sections for safety, features, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Engine with decompression valve, anti-vibration system, Quickstop® chain brake, side-access chain tensioner, automatic and manual chain oiler, and STIHL Ematic™ guide bar lubrication system.

Feature	Description
Engine Power	High-performance 2-stroke engine with decompression valve for easier starting
Anti-Vibration System	Reduces operator fatigue during extended use
Quickstop® Chain Brake	Inertia-activated safety feature to stop the chain in kickback situations
Side-Access Chain Tensioner	Allows for easy chain adjustment without tools from the side of the saw
STIHL Ematic™ System	Efficient guide bar lubrication system for reduced oil consumption
Automatic Oiler	Provides continuous lubrication to the bar and chain during operation
Pre-Separation Air Filtration	Extends air filter service intervals in dusty conditions
Master Control Lever	Single lever for choke, start, and run positions
Fuel and Oil Caps	Large, easy-to-open caps with retaining chains
Spark Arrestor Muffler	Reduces exhaust emissions and spark hazard

Safety Information

Read and understand all safety instructions before operating the chainsaw.

1. Personal Protective Equipment (PPE): Always wear chainsaw chaps or pants, safety glasses, hearing protection, gloves, and sturdy boots.
2. Clear Work Area: Ensure the area is free of obstacles, bystanders, and animals.
3. Secure Workpiece: Never hold the wood with your leg or foot. Use a sawhorse or log stand.
4. Kickback Awareness: Be aware of the kickback zone (upper quadrant of the guide bar tip). Maintain a firm grip.
5. Chain Brake Check: Test the chain brake functionality before each use.

WARNING! Failure to follow safety instructions can result in serious injury or death. Never operate a chainsaw when tired, ill, or under the influence of drugs or alcohol.

Assembly & First-Time Setup

Unpack and inspect all parts. Assemble the chainsaw on a clean, stable surface.

1. Attach Guide Bar and Chain: Place the bar onto the studs, fit the chain around the bar sprocket and onto the bar rails, ensuring cutting teeth face forward on top. Install and hand-tighten the bar nuts.
2. Tension the Chain: Using the side-access tensioner, adjust until the chain fits snugly against the bar but can still be pulled around by hand. Tighten bar nuts securely.
3. Fill Fluids: Add STIHL 50:1 2-cycle engine oil mix to the fuel tank. Fill the separate oil tank with STIHL chain oil or equivalent.
4. Final Check: Ensure all fasteners are tight, the chain brake is disengaged, and the chain moves freely.

CAUTION! The chain is extremely sharp. Always wear heavy-duty gloves during assembly.

Specifications

• Engine Displacement: 55.5 cc (3.4 cu. in.)
• Power Output: 3.0 bhp (2.2 kW)
• Fuel Tank Volume: 16.9 fl. oz. (500 ml)
• Oil Tank Volume: 11.8 fl. oz. (350 ml)
• Recommended Guide Bar Lengths: 16" to 20"
• Chain Pitch/Gauge: .325" / .063" (typically)
• Weight (Powerhead): Approximately 12.8 lbs (5.8 kg)
• Sound Power Level: 114 dB(A)
• Vibration Levels (Front/Rear Handle): 4.5/2.5 m/s²
• Warranty: Limited warranty for professional/commercial use. See dealer for details.

Controls and Components

Familiarize yourself with all controls before starting the engine.

Right Side: Throttle trigger, throttle trigger lockout, front hand guard/chain brake, Master Control Lever (choke/start/run), decompression valve.

Left Side: Rear handle, chain catch, side-access chain tensioner, oil filler cap.

Top/Other: Fuel filler cap, spark plug, air filter cover, muffler, starter grip.

Operation: Master Control Lever combines functions. Push down for choke (cold start), pull up past resistance to set to start position, release to run position after starting. The throttle trigger lockout must be depressed before the throttle trigger can be engaged.

Operation Guide

Starting the Engine (Cold):

1. Engage the chain brake by pushing the front hand guard forward until it clicks.
2. Press the decompression valve (if equipped).
3. Set Master Control Lever to choke position (full down).
4. Pump the primer bulb (if equipped) until fuel is visible.
5. Place saw on ground, hold rear handle with right foot, grip front handle with left hand.
6. Pull starter rope sharply until engine fires (usually 1-3 pulls).
7. Immediately move Master Control Lever up to the half-throttle (start) position.
8. Pull starter rope again to start engine. Let run briefly, then blip throttle to disengage start position.

Starting (Warm): Follow steps 1, 6, and 8, beginning with Master Control Lever in the run position.

Cutting: Disengage chain brake. Use full throttle for cutting. Let the saw do the work; do not force it. Be aware of pinch points, especially when cutting logs under tension.

Maintenance Schedule

Interval	Task
Before Each Use	Check chain tension, sharpness, and lubrication. Check all fasteners. Test chain brake.
Daily (or every 3-5 tanks)	Clean air filter. Check spark plug condition.
Weekly (or as needed)	Clean cooling fins, guide bar groove, and oil outlet holes. Clean exterior of saw.
Monthly (or every 20 hrs)	Inspect fuel filter and replace if clogged. Check anti-vibration elements.
Annually (or every 100 hrs)	Have spark arrestor screen cleaned by a dealer. Comprehensive inspection by an authorized STIHL dealer.

Chain Sharpening & Tensioning

A sharp, properly tensioned chain is critical for safety and performance.

1. Tensioning: Loosen bar nuts. Turn side-access tensioner screw clockwise to tighten chain. Chain should snap back when pulled away from the bar but not sag from the bottom. Retighten bar nuts securely.
2. Sharpening: Use a round file matching the chain's pitch (e.g., 5/32" for .325" pitch). File each cutter at the manufacturer's specified angle (typically 30°), using a filing guide for consistency. File all cutters to the same length. Lightly file down depth gauges (rakers) with a flat file and gauge.

Tip: Sharpen the chain at the first sign of dullness (producing fine dust instead of chips).

Fuel & Lubrication

Fuel: Use only fresh, high-quality unleaded gasoline (min. 89 octane) mixed with a premium 2-cycle engine oil at a 50:1 ratio. We recommend STIHL HP Ultra oil. Never use fuel older than 60 days. Do not use automotive oil or fuel intended for 4-cycle engines.

Chain Oil: Use STIHL chain oil or a high-quality biodegradable chain oil for optimal bar and chain life and reduced fling-off. In cold weather, use a winter-grade oil.

WARNING! Fuel is highly flammable. Refuel in a well-ventilated area with the engine stopped and cool. Wipe up any spills immediately.

Storage Instructions

For storage longer than 30 days:

1. Drain all fuel from the tank and run the engine until it stops to clear the carburetor.
2. Remove the spark plug, add a teaspoon of engine oil into the cylinder, pull starter rope slowly to distribute, then reinstall plug.
3. Thoroughly clean the entire saw, especially the cooling fins, air filter, and guide bar.
4. Remove the chain, clean it in solvent, dry, and coat with oil. Store chain and bar separately.
5. Store in a dry, secure place, out of reach of children.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	No spark, old fuel, flooded engine, clogged air filter, incorrect starting procedure	Check spark plug. Use fresh fuel. Follow correct starting procedure with choke. Clean air filter.
Engine starts then dies	Clogged fuel filter, dirty carburetor, faulty spark plug, vent in fuel cap blocked	Replace fuel filter. Clean or replace spark plug. Ensure fuel cap vent is clear.
Loss of power	Dirty air filter, clogged spark arrestor screen, dull chain, incorrect fuel mix	Clean air filter and spark arrestor screen. Sharpen chain. Use correct 50:1 fuel mix.
Chain does not oil	Empty oil tank, clogged oil passages, faulty oil pump, wrong oil (too thick in cold)	Fill tank. Clean oil outlet hole in bar and saw. Use correct oil. Have pump checked by dealer.
Excessive vibration	Loose components, unbalanced/damaged chain, worn anti-vibration buffers	Tighten all fasteners. Check chain balance and condition. Inspect anti-vibration elements.
Chain throws off bar	Improper tension, worn bar rails, damaged drive links on chain, worn sprocket	Properly tension chain. Inspect bar for wear ("curling" of rails). Replace worn bar, chain, or sprocket.

Service: For repairs beyond basic maintenance, contact an authorized STIHL servicing dealer. Use only genuine STIHL replacement parts.

Support: Visit www.stihlusa.com or contact your local STIHL dealer.